tools/gn: Remove fallback to direct_dependent_configs.

If public_configs were undefined we would fallback to
direct_dependent_configs.

we can remove this now, since we converted all the projects to
public_configs already.

BUG=None
R=brettw@chromium.org

Review URL: https://codereview.chromium.org/1307223009

Cr-Original-Commit-Position: refs/heads/master@{#346769}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 5591967b16af40155e7feb77efd6410b6c94a4ef
1 file changed
tree: 1023876ae831dcc46a4f8792e1c58bad45be104e
  1. tools/